Control mechanism



Nov. 17, 1959 H. BERESFORD ETAL 2,913,188

CONTROL MECHANISM 2 Sheets-Sheet 1 Filed May 26. 1955 R Q mm /NVENTO/?5. HOB/7P7 BE/PESFO/QD DAV/D L. CALDEPWOUD Nov. 17, 1959 H. BERESFORD EI'AL 2,913,188

CONTROL MECHANISM Filed May 26, 1955 2 Sheets-Sheet 2 Q-J 54 Q- 4 HOBART BE/QESFOQD 14 T 7' OP/YEY.

United States Patent CONTRGL MECHANISM Hobart Beresford and David L. Calderwood, Ames, Iowa, assignors to Iowa State College Research Foundation, Inc., Ames, Iowa, a corporation of Iowa 7 Application May 26, 1955, Serial No. 511,247

3 Claims. (Cl. 241-35) This invention relates generally to material handling and conveying apparatus and more particularly to a control mechanism for such apparatus.

In grinding corn or the like, the corn is fed by a feeding elevator or conveyor to a grinding machine. Another conveyor is usually arranged in or near a corn crib or hopper for supplying corn to the feeding elevator. It frequently happens that the corn is periodically fed to the grinder in larger quantities than the grinder is capable of handling. As a result, the grinder becomes overloaded and the conveying apparatus must be manually shut down by the operator until the grinder has been cleared. Thus, constant supervision of the entire operation has been required It is an object of this invention, therefore, to provide improved control mechanism for the conveyors in a material handling system.

A further object of this invention is to provide corn trol mechanism which includes an actuating switch responsive in operation to an overload on a power means such as an electric motor.

Another object of this invention is to provide a control switch which is operativeiy associated with the drive belt of a motor such that the switch is actuated in response to an increase in tension in the belt.

A further object of this invention is to provide a control mechanism for material handling apparatus, having a working unit and a feeding unit therefor, which is operable to shut oh? the feeding unit when the working unit is overloaded and to start the feeding unit when the load on the working unit has been decreased.

Another object of this invention is to provide a con trol mechanism for material handling apparatus, having a feeding unit and a supply unit therefor, which is op erable to shut off the supply unit in response to the amount of material being carried on the feeding unit.

Still a further object of this invention is to provide a control mechanism for material handling and conveying apparatus which is economical in cost, readily assembled with the apparatus and efficient in operation to pro vide for a continued automatic operation of the apparatus.

Further objects, features and advantages of this inven* tion will become apparent from a consideration of the following description when taken in connection with the accompanying drawing in which:

Fig. 1 is a diagrammatic elevational view of a grind ing and conveying apparatus, showing the control mech anism of this invention in assembly relation therewith;

Fig. 2 is a diagrammatic end view of a portion of the apparatus and control mechanism as taken along the line 2-2 in Fig. 1;

Figs. 3 and 4 are wiring-diagrams showing the circuits in the control mechanism of this invention, and showing in solid lines the switch position during normal running periods, and in dashed lines the switch positions caused by an overload in the comminution machine or grinder;

Fig. 5 is an enlarged elevational view of the power 'means or grinder motor for the apparatus shown in Fig.

1; and a switch for the control mechanism of this in vention assembled with the motor, with some parts being broken away and other parts shown in section for the purpose of clarity; and

Fig. 6 is an enlarged sectional view looking along the line 66 in Fig. 5.

With reference to the drawing, the material handling and conveying apparatus with which the control mechanism of this invention is adapted to be used, is illustrated in Fig. 1 as including a comminution machine or grinder lit, referred to generally herein as a working unit, and an elevator type conveyor 11, herein referred to generally as a feeding unit, for feeding material to the working unit It). A'conveyor 12, referred to herein generally as a supply unit, is arranged in a corn bin or hopper 13 for delivering corn to a hopper 14 arranged at the inlet end 16 of the feeding unit or elevator 11.

The grinder 10 is mounted on a horizontal frame 17 (Fig. 1) provided with wheels 18, and operates to grind material delivered thereto and to discharge the ground material through a movable spout 19 into a wagon or the like (not shown). A power means such as electric motor 21 has a drive pulley 24 arranged in the plane of a driven pulley 26 for the grinder 19. The motor 21 is carried on a base 22 having a downwardly extended peripheral rim 23 (Fig. 5) secured to the frame 17 in a side by side relation with the grinder 10. A belt 27 extends about the pulleys 24 and 26 for driving the grinder pulley 26 from the motor pulley 24. A second belt 23 is extended about a pulley (not shown) on the grinder shaft 29 and a pulley 31 on a blower shaft 32. The blower (not shown) driven by the shaft 32 operates to blow the ground material through the discharge spout 19.

As best appears in Fig. 5, the motor 21 is attached to the base 22 by means of upright bolts 33 extended through slots 34 (only one of which is shown) in the base 22. A transversely aligned pair of the bolts 33 (Fig. 6) are secured to the horizontal leg 36 of an angle member 37 (Fig. 5). The upright leg 38 for the angle member 37 carries a nut 39 mounted about the threaded end portion 41 of a horizontally extended bolt 42. The head 43 for the bolt 42 is arranged outwardly of the rim 23 on the base 22 and an unthreaded portion 44 of the bolt 42, arranged between the head 43 and the threaded portion 41, extends through the rim 23.

It is seen, therefore, that as a result of the connection of the bolt 42 with the motor 21, by means of the motor mounting bolt 33, angle member 37 and nut 39, a lateral movement of the motor 21 in one direction, moves the bolt a2 in the same direction. In other words, if the motor 21 is moved either to the right or the left, as viewed in Fig. 5, the bolt 42 is moved an equal amount in the same direction. 7

The bolt 42 extends through an opening 46 (Fig. 6) in the rim 23 and carries a channel shape switch supporting member 47 having a recessed base portion 48 received on an outwardly tapered projection or boss 49 formed on the rim 23 about the opening 46. Extended in a direction away from the rim 23, are a pair of vertically disposed leg portions 51 for the supporting member 47. A horizontal plate 52 (Figs. 5 and 6) is secured to and extended between the lower ends of the leg portions 51.

A microswitch unit 53 (Figs. 3 and '5), of a well known type is positioned against the rim 23 at a position below the plate 52. The switch 53 has a pair of contacts 56, normally biased into engagement with each other, and an operating pin 54 movable in a direction inwardly of the switch 53 (see arrow in Fig. 3) to move the contacts 56 out of engagement. A pair of screws 57 extended upwardly through the switch unit'53 and received in the plate 52 maintain the switch unit 53 in a fixed position.

A U-shape head member 58 (Fig. 6) mounted on the bolt portion 44 at a position adjacent the bolt head 43 has a base section 62 and a pair of parallel leg sections 59 guidably received between the leg portions 51 of the supporting member 47. A downwardly projected extension 61 (Fig. of the base section 62, arranged opposite the switch unit 53, carries a threaded actuating member or screw 63 arranged directly opposite the switch operating pin 54. A nut 64 on the screw 63 is engageable with the head member extension 61 to maintain the screw 63 in an adjusted position. Alternately arranged lock or spring washers 5i) and flat washers 55 positioned on the bolt 42 between the supporting member 47 and head member 58 constitute a spring means 60 for biasing the members 47 and 58 away from each other to a predetermined spaced relation.

It is seen, therefore, that on movement of the bolt 42 to the right as viewed in Fig. 5, the actuating member 63 is moved with the bolt 42. On movement of the member 63 into engagement with the operating pin 54 to depress the pin 54, the switch contacts 56 are moved apart to open the switch 53. Conversely, on movement of the bolt 42 to the left, as also viewed in Fig. 5, the actuating member 53 is moved out of engagement with the operating pin 54 to provide for the engagement of the contacts 56 and a consequent closing of the switch 53.

In use, the switch 53 is connected in series with a power means such as motor 72 (Fig. 3) for operating the elevator or feeding unit 11, with the source of current supply for the motor being indicated at 71. The bolt 42 is rotated to move the motor 21 laterally on the base 22 to adjust the tension in the belt 27. It is apparent that on such rotation of the bolt 42, within limits corresponding to the lengths of the slots 34 in the base 22 which limit the lateral movement of the motor 21, the spaced relation of the actuating .member 63 and the switch operating pin'54 is not effected since the spring means 66 on the bolt 42 acts to maintain a predetermined spaced relation between the actuating member 63 and the pin 54. The belt tension is thus adjustable independently of any adjustment of the actuating member 63 to effect operation of the switch 53. 7

When the elevator 11 is feeding grain to the grinder '10 in amounts readily acted upon by the grinder 10, the elevator 11 and the grinder 10 operate in the usual manner. However, when an unusually large amount of material is fed to the grinder 10 by the elevator 11 so as to overload the grinder, there is a resultant reduction in the speed of operation of the grinder 1t} and the speed of rotation of the grinder pulley 26. As a result, the pull of the motor pulley 24 on the belt 27 is increased to thereby increase the tension of the belt 27. The increased belt tension in turn causes a slight lateral movement of w the motor 21 in a direction toward the grinder 10.

By virtue of this lateral movement of the motor 21, the bolt 42 and the actuating member 63 are moved to the right, as viewed in Figs. 5 and 6. On a predetermined amount of such movement, the actuating member 63 (see Figure 3) is moved into contact with the switch operating pin 54 to move the switch contacts 56 apart to shut off the elevator motor 72 and discontinue the feeding of material to the grinder 10. The predetermined movement of the actuating member 63 required to open the switch 53 is readily adjusted by the manual setting of the member 63'. i I

The grinder 1t? acts upon the material already fed thereto until it has cleared itself and is operating at a normal speed. The tension in the belt 27 then decreases to the previously adjusted amount and the spring means 60 operates to move themotor 21 laterally in a direction to the left as viewed in Fig. 5. Such movement of the motor 21 returns the switch actuating member 63 to a position out of engagement with the switch operating pin 54. The

contacts 56 return to their engaged positions when the pressure of the actuating member 63 on the pin 54 is released, to thus start the motor 72 and resume a normal flow of material to the grinder 16.

To prevent a build up and overflow of material in the inlet hopper 14 for the elevator 11 during the time the elevator 11 is shut off, a control switch 73 is provided for shutting off the bin conveyor or supply unit 12 until the elevator 11 has resumed operation (Fig. 2).

An inverted V-shaped frame 74 (Figs. 1 and 2) is arranged in a straddling relation with the hopper 14 and carries, adjacent its upper end 76, a horizontal cantilever supporting arm or beam 77. A connecting structure 78, such as a pair of cables secured to a loop device and in turn attached to the beam 77 intermediate the ends thereof, is secured -to the hopper 14 so as to suspend the hopper 14 from the beam 77. The switch 73 (Figs. 2 and 4), which is of a micro switch type, is assembled on the motor base 22, has an operating pin 75 and is mounted on the free end 79 of the beam 77. The operating pin 75 is arranged directly below an upright actuating member 81 adjustably supported on the frame 74 and is normally in engagement with the member 81.

As shown in Fig. 4, the switch 73 is connected in series with a motor 83 for operating the bin conveyor 12, with the source of current for the motor 83 being indicated at 82. The switch 73 has the usual contacts 85 one of which is biased in a direction away from the other. To engage the contacts 85, the operating pin 75 which is biased in a direction outwardly of the switch 73 must be moved inwardly of the switch 73.

In use, when the hopper 14 is overloaded a predetermined amount with material delivered thereto by the conveyor 12, the weight of the hopper 14 and the material therein moves the free end 79 or" the beam 77 downwardly. As a result of the downward movement of the switch '73 (see the arrow in Fig. 4), the pin operating member 75 is moved out of a normal position in engagement with the actuating member 81. As a result, the operating pin 75 moves upwardly to in turn provide for a movement of the switch contacts 85 out of engagement. Flow of current to the motor 83 for the conveyor 12 is thus terminated so that the conveyor 12 is shut off, to thus discontinue any flow of material to the hopper 14. The predetermined amount of loading of the hopper 14 necessary to move the pin 75 out of engagement with the member 81 is readily adjusted by vertical adjustment of the member 81.

When the elevator 11 has been operated to move enough of the material out of the hopper 14 to reduce the weight of the hopper 14 on the beam 77, the beam free end 79 is moved upwardly to in turn move the switch operating pin 75 into engagement with the actuating member 81. In response to the engagement of the operating pin 75 with the actuating member 81, the contacts 85 are moved into engagement to again complete the'circuit for the bin conveyor motor 83 to provide for a resumption of the supply of material to the hopper 14.

From the above description it can be seen that this invention provides an automatic control for a material handling apparatus which includes a working unit 10, a feeding unit 11, and a supplying unit 12 to automatically provide for a continuous operation of the apparatus. Whenever the working unit 10 becomes overloaded, the feeding unit 11. therefor is automatically shut off until the working unit 10 has cleared itself and is operating in a normal manner. Likewise, whenever the feeding unit 11 is shut off, the supplying unit 12 therefor is also shut 01f until the feeding unit 11 has resumed operation, at which time operation of the supplying unit 12 is automatically resumed. The microswitches 53 and 73 are of a usual construction and are readily assembled with the apparatus to provide for an automatically controlled operation of the apparatus.

7 It is apparent that the microswitch 53 may be assembled, in the manner described above, with a motor for controlling or discontinuing the operation of any device connected in circuit with the switch 53, in response to increased tension in the drive belt of the motor.

Although the invention has been described with respect to a preferred embodiment thereof, it is to be understood that it is not to be so limited since changes can be made therein which are within the full intended scope of this invention as defined by the appended claims.

We claim:

1. Control means for use with a base having a motor movably mounted thereon and a belt arranged in a driven relation with said motor for driving a device having a variable load, and wherein said motor is movable in one direction in response to tightening of said belt, bias means for moving said motor in an opposite direction, said control means comprising a belt tension adjusting member supported on said base for rotational and longitudinal movement means connected to and extended between said adjusting member and said motor providing for movement of said motor in one direction on rotation of said adjusting member in one direction, a switch carried by said base, a switch actuating member adjustably mounted on said adjusting member and arranged in operative association with said switch, with said adjusting member and said actuating member being movable with said motor in response to an increase in the tension in said belt to provide for actuation of said switch by said actuating member.

2. In combination with a motor and a belt driven thereby for driving a device having a variable load, wherein the motor is movably mounted on a base for movement in one direction in response to tightening of said belt, bias means for moving said motor in an opposite direction, a control circuit including a switch mounted on said base, means connected between said base and said motor for adjusting the tension on said belt, and means connected to said motor for movement therewith and operatively associated with said switch for actuating said switch in response to tension changes in said belt.

3. In combination with a comminution machine, an elevator type conveyor for feeding material thereto, a first power means for said elevator, mounting means, a second power means for said machine mounted for linear movement on said mounting means, power transmitting means extending between said second power means and said machine and adapted to move said second power means in one direction due to an increased load on said second power means, biasing means operatively connected between said mounting means and said second power means for moving said second power means in an opposite direction, and a control circuit including switch means for controlling the operation of said first power means according to the position of said second power means on said mounting means.

References Cited in the file of this patent UNITED STATES PATENTS 760,713 Turbayne May 24, 1904 1,413,934 Ramsey et al Apr. 25, 1922 1,450,720 Gassman Apr. 3, 1923 1,878,983 Harris Sept. 20, 1932 1,949,119 Gibbs Feb. 27, 1934 2,100,848 Hardgrove Nov. 30, 1937 2,553,719 Palmer May 22, 1951 2,555,880 Freuchtel June 5, 1951 2,594,974 Mylting Apr. 27, 1952 

